ML19289F311

LER 79-011/01T-0 on 790302:engineering Review Determined Certain Containment Isolation Valves Incapable of Closing Against LOCA Pressure.Caused by Design Oversight.Future Mod to Expand Valve Open Alarm to Include Seal Low Pressure

ML19289F311
Person / Time
Site:	Peach Bottom
Issue date:	03/29/1979
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19289F307	List: ML19289F306 ML19289F311
References
LER-79-011-01T-01, LER-79-11-1T-1, NUDOCS 7906070215
Download: ML19289F311 (1)

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DOCM ET NUMS E R ab9 LVENTO4TE la RFP m tLast 4 ti, EVENT DESCRIPTION AND PROBASLE CONSEQUENCES h o 21 Engineering review determined certMn containment isolation valves in-_ _ , , . _ ,j F6T3-l l capable of closing against LOCA pressure. Analysis showed the valves will . ._ l

@l close if restricted to 37 degrees open.Further investigation and inspec , ,

,J Ql tion determined valve seal control system not seismically certified. 3

, l o a i valve seals found uninflated. Valves normally closed during opar.LOCA, o 7 l seismic event,and failure of control system on redundant valves would be _ ,)

gl required before event would have significant safety implications. ,_ 3 i ea n-

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36 31 40 41 47 43 44 4, CAUSE DESCRIPTION AND CORRECTIVE ACTIONS i O l Cause-design oversight-at discovery of inability to close, valves blocked _ g

,y closed-opening under sta. supt. authorization limited to 30 degrees.Upon , y i 2 I seismic concern, seismically designed control system installed.3uninflat- i i 3 i ed seals caused by linkage misadjust=ent-readjusted. Future modification ,_

j i 4 I expands existing " Valve open" alsrm to include seal low pressure.  ;

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